When I see, for instance, a Billiard-ball moving in a straight line towards another; even suppose motion in the second ball should by accident be suggested to me, as the result of their contact or impulse; may I not conceive, that a hundred different events might as well follow from that cause? May not both these balls remain at absolute rest? May not the first ball return in a straight line, or leap off from the second in any line or direction? All these suppositions are consistent and conceivable. Why then should we give preference to one, which is no more consistent or conceivable than the rest? All our reasonings a priori will never be able to shew us any foundation for this preference. - David Hume, An Enquiry Concerning Human Understanding 1748

He was prevented from from teaching at Universities because of his atheism. He offered Rousseau his protection in England in 1766, but eventually they fell out due to Rousseau's paranoias.

James Boswell hoped that Hume would keep his atheism on short leash when death knocked, and he went to the philosopher's bedside when illness was apparently winning its war with him to hear what Hume thought about his future at such a crucial hour. Indeed, Boswell hoped to be comforted by Hume's expected backslide of mind, but when asked whether 'it was not possible that there might be a future state [or afterlife],' Hume replied that 'it was possible that a piece of coal put upon the fire would not burn...'"